Sealed welding cable terminals



SePf- 29, 1959 J. s. wREFoRD Erm.

SEALED WELDING CABLE TERMINALS Filed Nov. 29, 1955 United States PatentO SEALED WELDING CABLE TERMINALS John S. Wreford, Franklin, and Frank L.Harris, Ann Arbor, Mich., assignors to Gar Wood Industries, Inc., acorporation of Michigan Application November 29, 1955, Serial No.549,630

3 Claims. (Cl. 174-15) The present invention relates to Water-cooledelectric cables for use on portable welding guns and particularly to thetype of cable shown in United States Patents 2,504,777 and 2,691,691.

In cables of the yabove type two conductors, each comprising a pluralityof twisted cables, are enclosed within a water-conducting hose or casingand separated from each other by a diametrically disposed insulatingseparator. The ends of the conductors are fastened, respectively, to apair of terminals, each of which is generally semicylindrical in crosssection. The flat inner faces of the terminals are separated by a flatseparator sheet of insulating material which merges with the insulatingseparator within the hose or casing. The arrangement and form of theterminals is such that the hose may be withdrawn olf the terminalsforrepair and replacement.

It has been found advantageous in the construction of terminals of theabove type to form the insulating sheet between the terminal parts of arelatively hard, heat-resisting material but such insulating materialshave been found to provide an inferior seal, with the result thatdiiculties have been encountered with leakage of the cooling water whichis circulated through the cable housing and is usually under water mainpressures of 60 to 7() pounds per square inch.

It is an object of the present invention to provide an improved terminalassembly having the advantages of the above described construction and,at the same time, an effective and novel form of seal which will preventthe leakage of water.

Other objects will become apparent from the following specification, theaccompanying drawings and the appended claims.

In the drawings:

Figure 1 is a longitudinal section through one end of the cable showingthe improved terminal construction;

Fig. 2 is a transverse section taken on the line 2 2 of Fig. 1;

Fig. 3 is an elevational view looking at the iiat side of one of theterminal elements;

Fig. 4 is a longitudinal section taken on the line 4-4 of Fig. 3; and

Fig. 5 is an end view of one ofthe terminal elements, which isillustrated in Figs. 3 and 4 and is taken on the line 5 5 of Fig. 3.

As best shown in Figs. 1 and 2, the cable comprises a hose-like casing 1containing a pair of conductors 2 and 3, each formed of three braidedcopper wire cables. The two conductors are separated and insulated fromeach other by a diametrically positioned sheet of molded rubber or resin4. In order to provide a clear passage for the iiow of cooling water,the assembly also includes a pair of coiled spring elements 5, onepositioned on each side of the insulating member 4. The springs 5terminate short of the ends of the conductors, and short lengths ofmetal tubing 6 are secured to the ends of the springs by shortoverlapping coil springs of slightly larger diameter to conduct coolingwater to the springs. The complete assembly of the conductors, coiledspring and insulating separator 4 are twisted throughout the length ofthe cable, as best indicated in the right-hand portion of Fig. 1.

The cable terminal assembly comprises a pair of terminal elements '7 and8 having generally at inner surfaces which seat against an intermediateinsulating sheet 9 which is of the full width of the terminals andextends into a slot formed in the extremity of the insulating separator4. The two terminal elements are clamped together and against theinsulating sheet 9 in any suitable manner, as by a cap screw 10, whichis insulated from the terminal 7 by an insulating bushing 11 and whichis threaded into a tapped opening in the terminal element 8 in themanner best shown in Fig. l.

The terminal elements 7 and 8, which, except for the openings for screw10, are identical in construction, are each formed of an inner section12 and an outer section 13 having a common flat surface 14 which seatsagainst the insulating sheet 9. The inner section 12 is generallysemicylindric in cross section, as best shown in Fig. 5, whereas theouter section is provided with a flat outer surface 15 and provides ameans for attachment to a welding gun.

The dat interior surface of each terminal element is provided with arecess 16 which receives the end of the conductor 2 or 3. After theconductor is inserted in the recess, a deformable wall portion 17 whichbridges the recess 16 is compressed downwardly to clamp the conductorcables together with 4the ends of the springs 5 and the inner ends ofthe tubes 6 within the recess and establish a firm electric connectionbetween the conductor and the terminal. This brings the upper surface ofthe bridging portion 17 to or below the level of the fiat surface 14 sothat the brid-ging section will not interfere with the flat separatorsheet 9 in the final assembly. The tube sections 6 prevent collapse ofthe springs 5 due to the clamping force exerted by portion 17 When theterminal elements are secured to the conductors and are also clampedtogether against the separator sheet 9, the casing or hose 1 may bepulled over the terminals into its final position illustrated in Fig. 1,and is then securely clamped to the cylindrical outer surface formed bythe terminal elements by means of strap clamps 13 and 19. The outerperipheries of the terminal elements may be provided with a plurality ofcircumferential grooves 20 into which the hose is compressed to assistin preventing leakage between the interior of the hose and the exteriorof the terminal elements.

As best shown in Fig. l, a portion of the semicylindrical section 12 ofeach terminal projects beyond the end of the hose or casing 1 and isprovided with a pair of tapped openings 21 which communicate with therecess 16 through longitudinal recesses 22 formed in the inner faces ofthe terminal elements. The tapped openings 21 may be used to connecthose fittings for connection to a source of cooling water. Either one orboth of the openings may be connected directly to a supply of coolingwater, or one of the tapped openings 21 may be plugged, as shown in Fig.l, by a plug 23, in which event the insulating sheet 9 is provided witha central opening aligned With the tapped openings 21 and through whichwater may flow.

In the construction above described, leakage of water between thecontacting flat surfaces of the terminal elements and the insulatingsheet 9 is prevented by means of a pair of sealing strips which arepositioned in grooves formed in the iiat faces of the terminal elements.As best shown in Figs. 3 and 4, each terminal element is provided with agenerally U-shape groove 24 which, at its center portion, extends outand around the recesses 22 and includes endfportionsiiwhich lie at theedges of -the at surface of the terminal element at a regionenelement-f26 of nubherflor rubber-like-material whichrispreferablyg'eircular in cro sssection As best shownm in Fig. 4,theggroove-24 ,is generally-rectangular, andthe sealing element 26.;hasva diameter slightly in excess of the--depth'offthevgroovelso that itwill be compressed betweenffthe terminalfelement andthe insulating sheet9 upon assembly and .perform a sealing function. The strip Vis the full'length of the groove 24 including its end-portionsZSgg-and,consequently, the ends of the strip are: sealed not-,only againstvtheterminal and theflat insulating sheet 9 but also against theinterior ofthe hose at apoint inwardly disposed with 'respect to the end portionofthe-hose, .which is clampedfand sealed against the cylindrical outersurfacesof theterminal'elernents.

As a result, the interior of the hose andalso the interior port-ion ofthe terminal, which will vcontain cooling water` undergpressure, arescaled,v from the exteriorfby a continuous seal `which includes the hoseand the two Y posed edges of said insulating member' acylindrical innerstrips of sealing material 26, thus'elfectively preventingV Y leakageofthe cooling water.

What is claimed is: l. A water-.cooled flexible welding cable comprisinga pair of iiexibleaconductorsa exible water-conducting, Y

having outer surfaces formed to denne with the exposed edges of saidVinsulating member a cylindrical inner section which lits withinone endof said casing, said casing having .a water-tightfit on saidVcylindrical section, the confronting4 surface of'at least one of saidterminal mem.- bers being provided with a water-,conducting recess whichextends from the inner end of the terminal to a point ou*- wardly.beyond the watertight tit of said casing with said cylindrical jsection,one Vof the confronting ksurfaces in thepair whichv includedV saidY oneterminal memberfbeing provided with an uninterrupted groOVe; whichvextends from Vone, side ledge Yof said; one terminal member at a point,within the casing to theOPPosite side'edge of said one. terminal memberat a point Within the casing, the intermediate portionV of said grooveextending generally longitudinally fof said one.terminal member andaround the outer ,-sideofsaidrecessin spaced'relationshiptheret to, Iandan elongated yieldahle4 sealing element` positioned` withinfsaidgroovein sealing engagement with said one terminal member and s aidA.insulating member, the end. portions Vof said `sealing elementbeing insealing enga-ge- 1 ment with the casing andterminating within thecasing.-

2. A water-cooled flexible welding rcable comprising a pair of flexibleelectrical conductors, a ilexible Vwaterconducting, hose-like casingenclosing said` conductors,- means within the casing .forielectricallyinsulating saidA conductors from eachother, a p air of terminallmembershaving` inner surfaces,` an insulating member intermediate said terminalmembers and havingsurfaces on opposite` section which ts within one endof said casing, said casing having a water-tight fit on said cylindricalsection, the confronting surface of at least one of said terminals beingprovided with a water-conducting recess which extends from the inner endof the terminal to a point outwardly beyond the end of the casing and isspaced from the side edges of the confronting surface, one of theconfronting surfaces in thetpair'whichvincludes said-one terminal havingan uninterrupted groove which extends from one side edge of said'one'vterminal at a point within the Icasing to theoppositeside edge ofsaid one-terminal at Va pointv within the casing, theintermediate-portion of said groove extending; generally longitudinallyof.said1oneffterrninal beyond said casing and around the outer side ofsaid recess in spaced relation thereto, and a strip of yielding sealingmaterial compressed within said groove in sealing engagement with saidone terminal member and said insulating rnernbenthe end` portions ofsaid strip being in sealing engagement with the casing and terminatingwith# inthe casing.

3. A water-cooled flexible welding cable comprisinga' pair of exibleconductors, a flexible water-conducting,

hose-like casing enclosing said conductors, means withinv the casing,for electrically insulatingsaidconductors from eachother, a pair ofterminal members having inner surfaces,` an insulating memberintermediatesaid terminal members and having surfaces on opposite sidesthereof` which .confront said inner surfaceson said terminalmembers,respectively, to form two pairs ofconfronting ,surv faces,.the inner endportions of said terminal members. having outer surfaces. formed todefine with the exposed edges-of said insulating member a cylindricalinnersection v which fits within one end of said casing, said casinghaving a water-tight fit onsaid cylindrical section, the lconfrontingsurface of at least one of said terminals being provided with awater-conducting recess -which extends f from the inner `end .of theterminal to a point outwardly beyondthe endV of the casing and is spacedfrom the side edges of the. confronting surface, a radial water inletopening in said one terminal communicating with theouter end of saidrecess, the confronting surface of said one terminal being providedvwith an uninterrupted groove which extendsfrom one side edge of saidone terminal` at a point within the casng'to the opposite side edgeofsaid one terminal at a point Vwithin the casing, theintermediate portionof said groove extending outwardly of the casing and around the outerside of said recess in spaced relation thereto, each end portion of saidgroove extending longi tudinally of the terminal at the edge of the'confronting tudinal portions of the groove in sealing engagement with4said casing, said strip of sealing material, in its free state,- beingcircular in cross section and having a diameter which is greater thanthe depth of the. groove.

References Cited in the iile of this patent g UNITED STATES 4PATENTS l2,691,691 Wreford Oct. 12,' 1954` 2,702,311 Botterill et al Feb. l5,1955 2,740,098 Phillips Mar.A 27,1956 2,752,579 Caldwell et al. June 26,1956 2,788,385 Doering et al. Apr. 9, 1957

